Migrating Owls Are Focus of Banding Study at Straits

Published in 2014 by The St. Ignace News

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In a wooded area just outside St. Ignace, a continual beeping noise can be heard from sundown to sunup. The source is a little box with a pin-sized light that continuously plays the call of a male sawwhet owl.

“They’re a little gregarious, so they’ll come to say hello,” said Ed Pike, a master bird-bander.

When they do, migrating sawwhets get caught in one of three nets arranged in a triangle around the lure. Mr. Pike and biologist Selena Creed claim the owls to determine their age, weight, and sex before banding them with a small metal loop around one foot — not so tight it restricts motion, but not so loose it can be wriggled off.

“Like a bracelet,” Mr. Pike said.

Another “passive” net, without a lure, is set up nearby to catch larger owls passing between the trees. These birds are banded, as well.

The bands, issued by the U.S. Geological Survey’s Bird Banding Laboratory, allow researchers to track birds’ movements. When a researcher catches an owl that has already been banded or finds one dead, the location is reported to the laboratory, creating a catalog of where the bird was and when.

It takes a long time to develop a comprehensive understanding of migration patterns, especially when it comes to raptors, since they don’t flock and have their individual territories, Mr. Pike said.

“We’re learning more and more, but the more you know, the more you know you don’t know,” he said.

Amateur birders assist researchers, but there are never enough qualified volunteers to count, catalog, and band birds passing through the Straits of Mackinac area, an important point in raptor migration. Raptors are a group of birds of prey that includes hawks, eagles, falcons, and owls.

To help with this, a group of regional Audubon Societies and individuals pooled their resources to form the Mackinac Straits Raptor Watch and hire Ms. Creed for the entire migration period, September 23 through November 10. They also hired Kevin Georg to study hawks during the spring migration north. Working outside Mackinaw City and assisted by volunteers, Mr. Georg identified more than 43,000 birds of prey crossing the straits.

“We’re excited to see this happen,” said Kathy Bricker of the Straits Area Audubon Society during a Saturday, October 11, birdbanding event. The nighttime program gave the public a chance to join Mr. Pike and Ms. Creed for an evening at work.

“Birds coming from South and Central America encounter big, open water for the first time at the Great Lakes,” Mrs. Bricker said.

Because of the energy it takes to fly over large bodies of water, birds prefer flying over land. As a result, birds passing through Michigan cluster at the narrowest crossing point, the Straits of Mackinac, to take advantage of favorable crossing conditions.

In autumn, when birds congregate on the northern side of the straits, the most owls can be caught outside St. Ignace. In spring, Mackinaw City is favorable.

This information can be used to indicate what types of development are appropriate for which areas, Mr. Pike said. Because the area is so important in raptor migration, large wooded areas are necessary to shelter them as they wait to make their crossing and rest after their flight.